A planned, five-day strike this week at University of California hospitals was averted Sunday after school officials and the union representing patient care technical workers reached a tentative agreement.

The proposed four-year contract covers 13,000 workers and could end months of tension between the university system and the union, which represents nursing aides, certified nursing assistants, magnetic resonance imaging technologists and other employees. A ratification vote is scheduled for Wednesday and Thursday.

"It was very encouraging to see UC do what they did, which was come back to the table and bargain in good faith," said Todd Stenhouse, a spokesman for the American Federation of State, County and Municipal Employees, Local 3299.

The workers had been planning to strike Monday morning at all five UC medical centers, in Davis, Irvine, Los Angeles, San Diego and San Francisco. They staged two brief strikes last year, walking off the job for two days in May and one in November.

The proposed contract includes raises totaling 24.5 percent over four years, according to a statement from the university system. Workers in lower salary tiers won't face increases in their health care benefit rates. And according to the union, the university system dropped a late demand for more authority to impose layoffs.

In return, the union agreed to changes in the pension plan. The new agreement adopts the same funding formula hammered out last year between the UC hospitals and the California Nurses Association, increasing the amount that employees contribute to their pension plans. Starting in July, that amount will rise from 6.5 percent of their pay to 9 percent, according to the union.

"There was true compromise by both sides to reach this agreement," said Dwaine Duckett, UC vice president for human resources, in a prepared statement. "This ends nearly two years of very challenging negotiations and serves as a foundation for UC and AFSCME to build on going forward."

This month, 97 percent of the university system's patient care technical workers voted to authorize a strike, complaining that the university system had unilaterally imposed contract changes and cut benefits. They also complained that a UC demand for greater flexibility in laying off employees could have left hospitals dangerously short-staffed.